JP5500766B2 - X-ray imaging device - Google Patents

Abstract

An X-ray imaging apparatus includes an X-ray imaging means (13), rotating means (12, 18) configured to rotate the X-ray imaging means relative to a subject on an axis of rotation (c), supporting means (19, 20) configured to support the subject, and a limiting means (31) configured to limit the range in which the X-ray imaging (13) means is moveable along the axis of rotation (c) depending on the position of the supporting means (19, 20) relative to the axis of rotation (c).

Description

  The present invention relates to an X-ray imaging apparatus that obtains an X-ray image from transmitted X-rays of a subject while rotating the subject side.

  Conventionally, radiation is irradiated from the outer periphery of the subject, the radiation transmitted through the subject is detected and converted into an image signal, and the image signal is reconstructed to obtain a three-dimensional cross-sectional image of the subject. The CT apparatus (Computed Tomography) to be constructed is used in the medical field.

  In this CT apparatus, a radiation source and a radiation detector are paired with the subject interposed therebetween, and while rotating around the subject in a spiral manner around the virtual body axis of the subject, A helical scan CT method that detects the intensity of transmitted radiation at a number of rotational positions is common.

  On the other hand, in recent years, a method of obtaining a tomographic image by rotating the subject side between a fixed radiation source and a radiation detector has been proposed. In this type of CT apparatus, a two-dimensional planar sensor is used as a radiation detector, and a fluoroscopic image necessary for reconstruction of a three-dimensional image is acquired by a single scan by irradiating cone-shaped radiation. be able to. Further, the continuous movement in the body axis direction, which is indispensable in a normal CT apparatus, is unnecessary.

  In the imaging method according to Patent Document 1 in which imaging is performed by rotating a subject, it is necessary to rotate the subject while stabilizing the posture of the subject while ensuring the safety of the subject. And the apparatus which has a countermeasure with respect to this is proposed.

  Japanese Patent Application Laid-Open No. 2004-228561 proposes an apparatus for photographing a patient by supporting the subject in a middle waist posture by providing a support member on the rotating table in order to suppress body movement of the subject. Patent Document 1 discloses a means for preventing a rotating lower limb from contacting a surrounding non-rotating portion by providing a lower limb guard in front of the subject. By arranging the subject in this way, it becomes possible to perform CT imaging with high throughput, and is being applied to chest screening instead of general still image imaging.

  Patent Document 2 proposes an apparatus that detects state information of a subject support member and controls rotation of a rotary table according to a detection result in order to ensure safety.

  On the other hand, since a large two-dimensional planar sensor is used as a radiation detector, these imaging apparatuses are generally expensive. In addition, in order to effectively utilize a limited installation space in a hospital, it is desired to perform both different imaging forms of CT imaging and general still image imaging using a single imaging apparatus. On the other hand, in Patent Document 1, the subject support member is moved and retracted from the X-ray irradiation range, thereby creating a space on the rotating table and performing still image shooting, and CT scanning with one apparatus. And a photographing apparatus that can be used for general still image photographing.

JP 2005-205082 A JP 2006-43193 A

  When performing CT imaging with such an imaging apparatus, the distance between the subject and the X-ray imaging unit is in contact during rotation in order to ensure a wide reconstruction area and to reduce image blurring. It is desirable that the distance is as close as possible. For this reason, in actual imaging, the position of the X-ray imaging unit needs to be arranged closer to the subject than the arrangement shown in Patent Document 1.

  Thus, as shown in FIG. 5 of the conventional example, the lower limb Pa of the subject P on the rotary table 2 moves under the X-ray imaging unit 3 during the rotation during the X-ray irradiation from the X-ray tube 1. It will be arranged to pass. Further, when the lower limb guard 4 is provided in front of the subject P, the lower limb guard 4 also passes under the X-ray imaging unit 3. Therefore, at the time of CT imaging, it is necessary to set the position of the X-ray imaging unit 3 within the vertical movement range L1.

  On the other hand, at the time of still image shooting, as shown in Patent Document 1, using a moving means provided below each subject support member, the subject support member is retracted from the imaging region, and the subject is exposed to X-rays. An image is taken close to the imaging unit and in close contact with the exterior of the X-ray imaging unit.

  In general still image photography, it is desired that the whole body can be photographed from the head to the lower limbs in the examination performed first for all diseases. For this reason, it is necessary to configure the vertical position of the X-ray imaging unit 3 so that the X-ray imaging unit 3 can move over a wide range compared to CT imaging.

  However, if the movable range of the X-ray imaging unit 3 is configured to be movable over a wide range for still image imaging, the X-ray imaging unit 3 moves more than necessary in CT imaging. For this reason, it may be set to an inappropriately low position, and contact between the X-ray imaging unit 3 and the subject support member or the lower limb Pa of the subject P may occur during rotation, which may impair safety. In order to ensure safety, it is necessary to pay attention to the position setting of the X-ray imaging unit 3, and as a result, the operability may be deteriorated.

  The same problem occurs when the imaging mode is changed, and after the general still image is captured at a low position, the subject support member is moved and the X-ray imaging unit 3 is changed to the CT imaging mode. If the rotary table 2 is rotated in the positional relationship, the safety may be impaired as described above.

  In addition, in an imaging apparatus that performs imaging by rotating a subject, a CT apparatus using a planar sensor does not require movement in the body axis direction, which is necessary for a normal helical scan CT apparatus. Conversely, during CT imaging, imaging must always be performed from multiple angles at the same height, and in an imaging apparatus capable of adjusting the height of the X-ray imaging unit, the X-ray imaging unit can move up and down during CT imaging. If this is done, correct images cannot be acquired and reconstruction cannot be performed. Since the conventional apparatus does not have means for forcibly prohibiting the raising / lowering during rotation, there is a risk that the raising / lowering is performed during photographing.

  An object of the present invention is to provide an X-ray imaging apparatus capable of obtaining an effective image for diagnosis without compromising the operability and safety of the height setting of the X-ray imaging unit, which is combined with CT imaging and general imaging. It is to provide.

  Another object of the present invention is to provide an X-ray imaging apparatus with high reliability that prevents the X-ray imaging unit from moving up and down during CT imaging.

In order to solve the above-mentioned problem, an X-ray tube and an X-ray imaging unit are arranged facing each other with the subject interposed therebetween, and the subject on the rotary table is irradiated with X-rays while rotating the rotary table. In an X-ray imaging apparatus for imaging a tomographic image of a subject by CT imaging,
A subject support member for fixing the subject's imaging target site;
First moving means for moving the subject support member between the CT imaging position and a position outside the imaging range;
Second moving means for moving the X-ray imaging unit in the vertical direction;
When the subject support member is at the CT imaging position, the second moving means vertically moves the X-ray imaging unit when the subject support member is at a position outside the imaging range. The range of movement in the direction is limited to be shorter.

  According to the X-ray imaging apparatus of the present invention, since the moving range of the X-ray imaging unit is limited to a range where no contact occurs during CT imaging, the safety is high and the operability is excellent.

  In addition, the risk of contact that occurs when switching between still image shooting and CT imaging is prevented, and even if the lifting / lowering operation is mistakenly performed during rotation, the position of the X-ray imaging unit remains. It can be prevented from being changed.

The present invention will be described in detail based on the embodiment shown in FIGS.
FIG. 1 is a configuration diagram of a state viewed from the side in a CT imaging state in which imaging is performed while rotating a subject. In front of the X-ray tube 11, an X-ray imaging unit 13, which is a flat sensor, for example, is disposed facing the subject P on a rotary table 12 that can rotate 360 °. The X-ray imaging unit 13 is attached to the support column 15 via the slide unit 14, and the slide unit 14 is driven up and down by the elevation drive unit 16, and the lower limit position of the X-ray imaging unit 13 is detected by the imaging unit position detector 17. It is like that.

  The rotary table 12 is supported by a rotary drive unit 18, and on the rotary table 12, a chair 19 on which the subject P sits, a backrest 20 on which the subject P adheres to the back, and a lower limb Pa of the subject P. A lower limb guard 21 is provided to protect against X-rays.

  The chair 19 is located in the vicinity of the rotation axis C of the rotary table 12, and the subject P makes his / her back close to the backrest 20 while sitting on the chair 19. The backrest 20 is long in the vertical direction, and the cross section thereof is an arc shape that allows the back of the subject P to be in close contact with the backrest 20. Yes. Further, the horizontal position of the backrest 20 is such that the virtual body axis of the subject P is substantially coaxial with the rotational axis C of the turntable 12 in a state where the imaging target portion Px of the subject P is in close contact with the backrest 20. It is arranged to become.

  The lower limb guard 21 has an arc shape along the outer shape of the circular turntable 12, and prevents the lower limb Pa of the subject P from contacting the non-rotating portion around the turntable 12 during the rotation.

  The chair 19 and the backrest 20 as the subject support members are positioned outside the imaging range from the CT imaging position so as not to interfere with the still image imaging by the chair slide member 24 and the backrest slide member 25 as the first moving means. It is possible to move to. The positions of the chair 19 and the backrest 20 are detected by a chair position detector 26 and a backrest position detector 27.

  The output of the control unit 31 that controls the X-ray imaging apparatus captures the outputs of the X-ray generation apparatus 32, the elevation driving unit 16, the rotation driving unit 18, and the X-ray imaging unit 13 that are output to the X-ray tube 11. It is connected to the image capturing unit 33. The control unit 31 is connected to outputs of the photographing unit position detector 17, the chair position detector 26, the backrest position detector 27, and the foot switch 34. Further, the output of the image capturing unit 33 is connected to the image processing unit 35.

  The slide unit 14 controls the X-ray imaging unit 13 to move up and down variably in the vertical direction along the support column 15 by a lift drive unit 16 as a second moving means. The movement and stop by the elevating drive unit 16 are performed by an instruction from the control unit 31 in response to an operation from the foot switch 34 by an engineer. Further, whether or not the vertical position of the X-ray imaging unit 13 is in the upper and lower range L1 of CT imaging is detected by the imaging unit position detector 17 and the detection result is transmitted to the control unit 31. The lower limit position of the vertical range L1 is limited to a position where the lower limb guard 21 of the subject support member does not enter the imaging region, and is set to a height that does not cause contact with the lower limb Pa of the subject P.

  The selection of whether to perform CT imaging or still image imaging is detected by a chair position detector 26 and a backrest position detector 27 that are support member position detection means, and the detection result is transmitted to the control unit 31.

  At the time of CT imaging, the control unit 31 drives the rotation driving unit 18 in accordance with the imaging request signal, and controls the rotation table 12 to rotate. When a predetermined rotational state is reached, X-ray exposure from the X-ray tube 11 begins and CT imaging is started. In this state, even if the foot switch 34 is operated, the control unit 31 does not raise or lower the X-ray imaging unit 13 and keeps the position of the X-ray imaging unit 13 constant. Images are obtained.

  In synchronization with this exposure, the control unit 31 controls the image capturing unit 33 to capture X-rays transmitted through the subject P as image data by the X-ray imaging unit 13, and the image processing unit 35 performs the test. A tomographic image of a three-dimensional image is obtained using image data from a 360 ° direction of the person.

  Note that the control method may be such that the X-ray imaging unit 13 cannot be raised or lowered while the rotary table 12 is rotating, regardless of the X-ray irradiation.

  FIG. 2 is a configuration diagram in which the chair 19 and the backrest 20 are changed from the CT photographing position to the still image photographing state, and the rotary table 12 is rotated 90 degrees clockwise from the state of FIG. 3 is a configuration diagram of this state as viewed from the side. The chair 19 is moved to both sides on the rotary table 12 by the chair slide member 24 and the backrest 20 is moved by the backrest slide member 25, so that the subject P can photograph the body in close contact with the X-ray imaging unit 13. It becomes.

  X-rays from the X-ray tube 11 pass between the chair 19 and the backrest 20 retracted on both sides and are irradiated to the subject P. In this case, since there is no shielding in the vertical direction, imaging of any part of the whole body from the head of the subject P to the lower limb Pa is possible in the range L2 of the X-ray imaging unit 13.

  In still image shooting, the X-ray imaging unit 13 may be set at a lower position in order to capture the lower limb Pa of the subject P. When switching to CT imaging after still image shooting, the X-ray imaging unit 13 is in the still image shooting position even if the chair 19 and backrest 20 are switched to the CT imaging mode. If the rotary table 12 is rotated in this state, there is a possibility of collision, and this embodiment has a mechanism for preventing this.

  The change of the chair 19 and the backrest 20 to the CT imaging position is detected by the chair position detector 26 and the backrest position detector 27, and a detection signal is sent to the control unit 31. However, the signal from the imaging unit position detector 17 is detected when the X-ray imaging unit 13 is not at the CT imaging position. In this case, the control unit 31 is controlled so as to maintain the stopped state even if the rotation operation is performed by an engineer, and an alarm that prompts the display unit (not shown) to raise the X-ray imaging unit 13. Is displayed.

  In this state, the control unit 31 validates only the operation on the ascending side of the up-and-down movement of the X-ray imaging unit 13. When the technician raises the X-ray imaging unit 13 with the foot switch 34, the alarm on the display unit disappears when the X-ray imaging unit 13 enters the movable range L1 during CT imaging. In addition to the alarm display, the X-ray imaging unit 13 may be controlled to automatically rise up to the lower end of the movable range L1 during CT imaging. This makes it possible to prevent problems that occur when switching between still image capturing and CT imaging is performed.

  FIG. 4 is a flowchart of a process for adjusting the vertical position of the X-ray imaging unit 13. When adjusting the position of the X-ray imaging unit 13, the engineer first operates the foot switch 34 (step S1). Based on signals from the chair position detector 26 and the backrest position detector 27, the control unit 31 determines whether or not the subject support members of the chair 19 and the backrest 20 are in the CT imaging position (step S2).

  In the case of CT imaging as shown in FIG. 1, while the signal from the imaging unit position detector 17 is in the range L1, the control unit 31 permits the ascending / descending operation according to the operation from the foot switch 34 (step S3). To S6). Then, the foot is released from the foot switch 34 at a desired position, and the elevation is stopped.

  However, when it reaches the limit position of the CT range due to the movement, it stops at that position and is controlled so as not to move up and down further (steps S4 to S8). Thus, the X-ray imaging unit 13 is always located within the CT imaging range L1 during CT imaging.

  As shown in FIGS. 2 and 3, when the subject support member is in a general still image shooting state, the control unit 31 is controlled by the foot switch 34 regardless of the signal from the shooting unit position detector 17. Is controlled so that the X-ray imaging unit 13 can be raised and lowered according to the input (steps S9 to S10). Thereby, at the time of general still image photographing, a wide range up to the vertical range L2 shown in FIG. 3 can be moved, and the whole body can be photographed from the head of the subject P to the lower limb Pa.

It is a block diagram of the CT imaging state of an Example. It is the block diagram which looked at the still picture photography state from the upper part. It is the block diagram which looked at the still picture photography state from the side. It is a flowchart figure of the raising / lowering operation | movement of a X-ray imaging part. It is a block diagram of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 X-ray tube 12 Rotary table 13 X-ray imaging part 14 Slide part 15 Support | pillar 16 Elevation drive part 17 Imaging | photography part position detector 18 Rotation drive part 19 Chair 20 Backrest 21 Lower limb guard 24 Chair slide member 25 Backrest slide member 26 Chair position detector 27 Backrest position detector 31 Control unit 32 X-ray generator 33 Image capturing unit 34 Foot switch 35 Image processing unit P Subject

Claims (3)

An X-ray tube and an X-ray imaging unit are arranged opposite to each other with the subject interposed therebetween, and the subject is obtained by CT imaging that irradiates the subject on the rotary table while rotating the rotary table. In an X-ray imaging apparatus for imaging a tomographic image of
A subject support member for fixing the subject's imaging target site;
First moving means for moving the subject support member between the CT imaging position and a position outside the imaging range;
Second moving means for moving the X-ray imaging unit in the vertical direction;
When the subject support member is at the CT imaging position, the second moving means vertically moves the X-ray imaging unit when the subject support member is at a position outside the imaging range. An X-ray imaging apparatus characterized by being limited so that a range of movement in a direction is shortened.   Rotation drive means for performing rotation control of the turntable, and the rotation drive means enables rotation of the turntable only when the vertical position of the X-ray imaging unit is within a limited movable range. The X-ray imaging apparatus according to claim 1.   Elevating control means for controlling the operation of the second moving means, and the elevating control means disables the movement of the X-ray imaging unit when the rotary table is rotating. The X-ray imaging apparatus according to claim 1.

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